Transport signals and transcription-dependent nuclear localization of the putative DEAD-box helicase MDDX28

被引:11
作者
Valgardsdottir, R [1 ]
Prydz, H [1 ]
机构
[1] Univ Oslo, Biotechnol Ctr Oslo, N-0349 Oslo, Norway
关键词
D O I
10.1074/jbc.M300888200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The human protein MDDX28 is a putative RNA helicase and a nucleocytoplasmic shuttling protein also localized to the mitochondria. Its localization is novel among RNA helicases. We have studied its intracellular targeting signals and show that the first 20 amino acids of MDDX28 are necessary and sufficient for both mitochondrial import and nuclear export of the protein. Mutation of the five leucines in the sequence to alanines abolished the mitochondrial targeting signal as well as greatly reducing the nuclear export signal, indicating that these signal sequences are highly overlapping. Two short stretches of basic amino acids separated by 44 residues were both necessary and sufficient for full nuclear localization. However, they were not absolutely essential, because the protein was present in 7% of the nuclei when both signals were mutated. This indicates that MDDX28 contains another unidentified weak nuclear localization signal(s). Three basic domains in the N-terminal half of the protein and its RNA binding ability were essential for nucleolar localization as well as transcription-inhibition-dependent localization to nuclear subcompartments. Two of these basic domains were the same as those constituting the nuclear localization signal, suggesting that they are responsible for bringing the protein into the nucleus to the sites of RNA binding. Our results indicate that MDDX28 nucleo-cytoplasmic shuttling is dependent on the availability of nascent RNA.
引用
收藏
页码:21146 / 21154
页数:9
相关论文
共 40 条
[1]  
Andersen JS, 2002, CURR BIOL, V12, P1, DOI 10.1016/S0960-9822(01)00650-9
[2]   Nuclear export of the DEAD box An3 protein by CRM1 is coupled to An3 helicase activity [J].
Askjaer, P ;
Rosendahl, R ;
Kjems, K .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2000, 275 (16) :11561-11568
[3]   Helicases: a unifying structural theme? [J].
Bird, LE ;
Subramanya, HS ;
Wigley, DB .
CURRENT OPINION IN STRUCTURAL BIOLOGY, 1998, 8 (01) :14-18
[4]   To be or not to be in the nucleolus [J].
Carmo-Fonseca, M ;
Mendes-Soares, L ;
Campos, I .
NATURE CELL BIOLOGY, 2000, 2 (06) :E107-E112
[5]   The contribution of nuclear compartmentalization to gene regulation [J].
Carmo-Fonseca, M .
CELL, 2002, 108 (04) :513-521
[6]   Nucleocytoplasmic shuttling of p130/RBL2: Novel regulatory mechanism [J].
Chestukhin, A ;
Litovchick, L ;
Rudich, K ;
DeCaprio, JA .
MOLECULAR AND CELLULAR BIOLOGY, 2002, 22 (02) :453-468
[7]  
Chiodi I, 2000, J CELL SCI, V113, P4043
[8]   Nuclear targeting of proteins: how many different signals? [J].
Christophe, D ;
Christophe-Hobertus, C ;
Pichon, B .
CELLULAR SIGNALLING, 2000, 12 (05) :337-341
[9]   CRM1 is an export receptor for leucine-rich nuclear export signals [J].
Fornerod, M ;
Ohno, M ;
Yoshida, M ;
Mattaj, IW .
CELL, 1997, 90 (06) :1051-1060
[10]   Paraspeckles: A novel nuclear domain [J].
Fox, AH ;
Lam, YW ;
Leung, AKL ;
Lyon, CE ;
Andersen, J ;
Mann, M ;
Lamond, AI .
CURRENT BIOLOGY, 2002, 12 (01) :13-25